Work pieces, including food products, are cut or otherwise portioned into smaller portions by processors in accordance with customer needs. Also, excess fat, bone and other foreign or undesired materials are routinely trimmed from food products. It is usually highly desirable to portion and/or trim the work pieces into uniform shapes, thicknesses, and/or sizes in accordance with customer needs. Much of the portioning/trimming of work pieces, in particular food products, is now carried out with the use of high-speed portioning machines. These machines use various scanning techniques to ascertain the size and shape of the food product as it is being advanced on a moving conveyor. This information is analyzed with the aid of a computer to determine how to most efficiently portion the food product into optimum sizes, weights, or other criteria being used.
Customers who purchase sandwiches and similar items from quick-service restaurants like to see some meat extending beyond or at least even with the bun perimeter, not hidden inside the bun. On the other hand, too much meat protruding from the bun, such as a long, thin piece of meat within a round bun, is undesirable as well.
Historically, determining shape compliance for portioned product has been carried out with dimensional template checking. Workers take samples of the portioned product and place them on a printed piece of plastic or other template showing the bun. Workers literally count squares (printed on the template) to determine the areas inside and outside of the bun.
Quality checks of sandwich bun coverage are performed both with raw product and with cooked product. Meat, fish, and poultry shrink when cooked, and does so non-uniformly. This makes manual prediction of whether or not the product will be appropriately sized a difficult task.